1. Field of the Invention
This invention relates to a method of manufacture of flexible tube containers, in particular plastics tube containers, and especially plastics tube containers of the type used for dispensing flowable materials such as, for example, toothpaste, cosmetic creams or edible pastes.
2. Discussion of Prior Art
A typical plastics paste tube container is made by shaping a flat plastics strip so that the longitudinal edges of the strip are brought into contact and welded together as the strip is advanced. The tube formed in this manner is typically substantially round or oval in cross-section, with one end being subsequently closed by a cap with a nozzle therein, and the other end being formed into a "fish tail" sealed end.
Such tubes are generally marketed in cartons for protection, ease of storage in boxes and for convenient display on shelves.
More recently there has been a development as illustrated in U.S. Pat. No. 5,299,689 to produce tube containers of square cross-section in order to avoid the need for an external carton. Square cross-section tube containers may be made by blow moulding techniques as shown in U.S. Pat. No. 5,299,689 or U.S. Pat. No. 5,383,577. Alternatively, U.S. Pat. No. 5,373,965 discloses a method of manufacturing tubes of square cross-section by a folding operation or by direct extrusion of square section tubular material.
Also dual chamber dispensing containers have been developed for the separate storage of components which interact when allowed to combine, the two components being combined on discharge from the container. Examples of such containers are shown in U.S. Pat. No. 5,328,056, U.S. Pat. No. 5,318,203, U.S. Pat. No. 4,528,180 and WO 94/19251.
Dual chamber flexible dispensing containers may comprise two independent tubular containers held in side-by-side relationship as shown in U.S. Pat. No. 4,528,180, U.S. Pat. No. 5,318,203 and WO 94/19251. In order to assemble the tubular containers side-by-side, the upper ends of the two containers formed into a D-shaped cross-section are provided with a D-shaped fitting, sometimes known as a shoulder, allowing the two containers to be held side-by-side and form a circular configuration which may be held together within a cylindrical cap. The prior art tubular containers shown in U.S. Pat. No. 5,318,203 and WO 94/19251 are generally made from tube of circular cross-section and are each deformed at one end to take up the D-shaped configuration whilst the remainder of the tubular compartment is substantially circular. After filling and formation of the `fish tail` sealed ends there is typically a graduation in the shape of the tubular container from the D-shaped cross-section end through an oval cross-section to the substantially flat tail end format.